1. Field of the Invention
This invention relates generally to measurement of mechanical properties of geo-materials, and more particularly, but not by way of limitation, to an apparatus that utilizes a cam to deliver cyclical impulse loads to a test specimen to determine, among other properties, the dynamic and resilient modulus of the test specimen.
2. Brief Description of Related Art
Numerous devices and methods for determining physical properties of geo-materials, such as soil and aggregate, are known in the art. Such testing devices and methods suffer from numerous drawbacks, such as equipment size and complexity, expense of manufacture and operation, and the large volume of specimen material required to perform testing. More specifically, testing the resilient modulus of soil requires obtaining and forming a soil sample from soil taken in the field or remolding a soil sample in the laboratory. The soil sample is then positioned within the testing apparatus where a confining pressure can be applied to the soil sample to simulate the pressure exerted on the soil in situ.
The testing apparatus applies impulse loads, usually cyclically, to the soil sample over a predetermined amount of time and measures the soil sample response via one or more sensors (e.g., linear variable differential transducers) to produce data indicative of the soil sample response. The data may then be utilized in conjunction with an algorithm to determine the resilient modulus of the soil.
Common testing apparatuses utilize either pneumatic or hydraulic systems to deliver impulse loads to the soil sample. Unfortunately, pneumatic and hydraulic systems are expensive to manufacture, operate, and maintain. Furthermore, because of their size, pneumatic and hydraulic systems are impractical for use in the field.
To this end, a need exists for an apparatus and method for evaluating mechanical properties of geo-materials that is portable, inexpensive to manufacture and operate, and which provides reliable results with a smaller volume of material. It is to such an apparatus and method that the present invention is directed.